Dual filter and connection shield



sept 7, 1948. l E. c. HALLETT 2,448,711

DUAL FILTER AND CONNECTION SHIELD Filed Sept. 28, 1945 /NVENTOR- Bro/v C. HALLE-r1'.

ATTORNEY Patented Sept. 7, 1948 DUAL FILTER- AND CONNECTION SHIELD Elton C. Hallett, Inglewood, Calif., assignor to Hallett Manufacturing Company, Inglewood, Calif., a corporation of California Application September 28, 1945, Serial No. 619,236

1 Claim.

` The invention relates to the shielding and protection of electric systems of internal combustion engines and is designed to prevent damage to the systems by moisture and to prevent electric radiations from spreading outwardly and interfering with the operation of nearby radio communication sets.

The electric ignition system of an internal combustion engine when in operation produces high frequency electric radiations which are apt to be picked up in a radio receiving apparatus carried b y the vehicle with sufcient force to interfere `with reception of the radio receiver. It is becoming increasingly important to eliminate or control all harmful electrie radiations on motor vehicles because of the increasing use of portable radio receiving apparatus. Although this has been important during the War on motorized combat equipment, it is likewise of importance in ordinary commercial vehicles where there is an advantage in being able to communicate with such vehicles from some central point while they are being driven about in service. Vehicles within the scope of this invention may be aircraft and marine craft as well as automotive vehicles.

Among the objects of my invention therefor is to provide a new and improved combination Waterproof and electric shield for electric units on combustion engines.

l `Another object of my invention is to provide a water tight box for housing electric units of the ignition .system of a combustion engine which is adapted to be opened sufciently to provide ready access to the interior when electric units are to be mounted therein and which is also provided with a tight fitting cover or lid easily placed upon the housing and sealed in place so that no water can Areach the interior.

tric units of certain types in place without it being f necessary to provide mountings on the electric units themselves.

With these and other objects in view my invention consists in the construction, arrangement and combination of various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claim and illustrated in the accompanying drawings, in which:

Fig. 1 is a plane view of the device with the lid removed and showing one of the terminal conn nections in section.

Fig. 2 is a longitudinal sectional view taken on the line 2-2 of Fig. l.

Fig. 3 is a cross sectional view taken on the line 3--3 of Fig. 1.

While it is not new in the art to provide shielding for electric systems generally in order to intercept the passage of electric radiations and although some attempts have been made to provide water resistant coverings of some kind or other for parts of the ignition systems of motor Vehicles there has not been to date a successful shield provided which Iwill accomplish both of these objectives. A metallic shield which would be effective in interrupting the transmission of electric radiations need not necessarily be water-proof or moisture-proof.' On the other hand there are many classes of water proofing which have no effect Whatever in preventing the transmission of electric radiations. Recent developments in automotive equipment ywherein vehicles are driven through water and deep mud, over miles of dusty unpaved roadways and into places Where dust, dirt, grease and moisture may collect in the operating parts of the vehicle has made necessary the elective protection and shielding of electric units in the system. Where vehicles are sent out on missions directed from a central control point there is need for constant communication with the vehicle, as for example, by radio. For effective radio communication interfering electric radiations from the engine ignition system must be controlled. This is true not only in war time but in peace time as well, a notable example of which is in police car control. When the electric systems of such vehicles are damaged as a result oi dust and moisture it not only interferes with successful operation oi the vehicle, but likewise interferes with successful operation of the radio communication system.

In an embodiment chosen to illustrate a formy of my device there is shown a shielding lter housing indicated generally by the reference character l0 and Icomprising a box Il and lid I2. The box has relatively high side walls and end walls providing an interior space I3 which is relatively deep. The box has a bottom I4, the ends of which are provided with ears l5 adapted to receive a bolt or screw for fastening the housing to a stationary portion of a combustion engine.

At one end o-f the housing is provided a single water proof terminal connection l 6. At the other end of the housing a pair of terminal connections of the same kind may be provided. At the top edges of the side walls there is provided a blunt ridge I1 which lextends peripherallyjaround the top of the edge of the box. For sealing the lid upon the box in closed position there is provided around the periphery of the lid a pair of parallel flanges I'B and I9, the flanges being spaced sufiiciently wide apart so as to Aaccommodate the top portion of the side walls adjacent the ridge, while at the same time leaving ample space on both sides of the walls. Within the space between the parallel flanges there is a packing 20 of some resilient rubber-like material. For `holding the lid in place upon the box there is provided a set of forked lugs 2| at the edges of the lid and a complementaryset of forked lugs 22 on the box. In this particular embodiment screws 23 are shown extending laterally into threaded engagement with pivot pins 2l! which arerotatably mounted in the lugs '22. The shanks of screws -23 are adapted to be received between the forked portions of the lugs 2| and have heads 26 together with washers adapted to bear against the tops .o'f the .lugs adjacent theilid 2.|.

In the interior of the box there 'is provided a partition wall 26 extending from one side of the box to the other. As appears particularly in Fig. 2, the top edge .of partition wall is located asubstantial distance below lthe top edge of the side walls and even lbelow the `lower edge of the flanges 8 and I9. The partition wall in effect forms a separate electrically shielded compartment 26 at one end of the box. To close the compartment and complete the electric shield there .is provided a metal cover 21 held in place by means of cap screws 28 at the corners.

In this embodiment two lter cases 29 are located within the housing in such a manner that they rest upon ybosses 30 at the bottom of the box, The tops of the bosses are parallel andin the same plane and spaced at -a distance above the bottom of the box. The -filter case therefore yrests upon the bosses and a space remains between the lbottom of the ilter case and the bottom ofthe box.

There is, howevenan electric connection between the case and the boss `in each instance.

In order to -hold the filtercases in place .there is provided for each 4one of them a bracket 3| having a iiat top lportion 32 'and wings 33 at the sides. The bracket is likewise provided with legs 34 atone end and feet 35 which in turn are lsupported by bosses 36. To vprovide a sufficient depth of metal in the bosses to receive a screw 37 without penetrating the bottom -of the box the bosses, in eiect, extend through the bottom and include an extension 36.

At the other end feach of the brackets is provided with laterally extending aps 38. These are secured to a lateral extension of the `partition 25, by means of .cap screws 39. It will .be noted that the partition 25 is provided with an aperture M3 for each filter communicating between the compartment and the remaining interior of the housing.

In this embodiment the drawing illustrates a filter inposition under each of the brackets `3l and each filter comprises a filter-cased! of metallic material. .A permanent .connection -42 is located at oneendof each filteradjacent the bottom of .the box anda 'permanent connection 43 4 is located at the other end remote from the bottom of the box. Each connection 43 extends through the aperture il@ of the partition into the compartment 26.

A lead line 44 extends between the permanent connection 42 and comprises a wire leading outwardly through one of the terminal connections iii. At the other end of the iter case-alead line 45 extends from the connection 43 outwardly through another of the terminal connections I6.

When the device is assembled each filter case is placed upon one of the bosses 3U and the bracket is then applied in such a manner that th'e top portion of the bracket presses the filter case down upon the boss. The feet 35 are fastened to bosses 36 and at the same time the ilaps 38 are fastened to adjacent portions of the partition. Wings 35 likewise tend to enclose and support the sides of the filter case. Mounted in this way th'e case is also in contact with the partition 26.

After the lter has thus been mounted -.and the connections made the lid is applied by-ip'ress- .ing the resilient packing down against the ridge 'IT and screws 23 are then swung into place fand tightened. The force of tightening .screws .253

draws the lid down against the top edgesof .the side walls so that they penetrate the .resilient packing and make a water tight seal. A metallic connection is made at the same time between the lid and the box through the screws 23. The box 'of course is grounded to the combustion lengine by having the ears 25 attached to the engine by means of suitable machine screws. There isfurther provided a sealed metallic connection between a sheathing 46 of a conduit 41 and th'eterminal connection so that a complete electric .shielding encloses the entire electric unit and fits connection,

Since the metallic connections ar-e all pro'- .tected by water proof seals there is eiected Ia combination of electric radiation resisting and water resistant shielding for twin lter'units 4disclosed herein in the form of a protective lvhousing which assures uninterrupted performance .of lthe vehicle under virtually all conditions.

VAlthough I have herein shown and described my invention in what I have conceived'to be the most practical and preferred embodiment, `it is recognized that departures maybe made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope ofthe claim so as to embrace any and all equivalent devices.

Having described my invention, what I rclaim as new and desire to secure by Letters Patent'is:

A shielded filter housing comprising a `lwater tight, metallic box having relatively 'high side walls, a cover for the box having a sealingire'cess encompassing the tops of the Walls, 'a resilient jpacking in the recess adapted to engage the tops `of the side walls forming a water pro'o'f Inonmetallic seal, and a metallic connection between :portions of the cover and the box, said box having fa lateral partition wall in the interior foririing'"a separate compartment for connections, a'separate metallic cover for the compartment spaced from the lid, a filter case anchoring bracket 'secured at fone end by a metal to metal contact't'o the f'side of the partition remote Vfrom the compartment .and at the other end to the bottom ofith'e box Aand adapted to anchor a lter 'case in the box in erect position with terminals at opposite ends thereof exposed respectively inside 'and .outside the compartment, and water proof terminal :con-

Jiections on the walls communicating with interior of the box respectively inside and outside the compartment for communication with' the respective iiiter terminals.

ELTON C. HALIEIT.

REFERENCES CITED The following references are of record in the le of this patent:

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